9 ways to make money by selling your body to science

Need some extra cash? If you want to help the science community (and potentially save some lives) there are some unconventional ways to make money by selling your body.

Below is a short list, though these strategies aren't all easy money:

Sell your blood plasma

Payout (per donation): around $50

Plasma is the largest component in human blood. It's a protein-rich liquid that contains mostly water but is also filled with enzymes, antibodies, and salts. This gooey, sticky yellow-ish stuff can be used to create therapies that treat people with blood clotting disorders, autoimmune diseases, and even burn victims. According to DonatingPlasma.org, donating plasma is often called "the gift of life," since synthetic therapies are not typically available for these problems.

During plasma donation, blood is drawn and an automated machine separates the plasma from other blood components, which are returned to the donor. Plasma donation pay varies from site to site, but the average payout is typically around $50 per donation. You can donate safely roughly once a month, according to the American Red Cross, and a typical session takes less than two hours. To find a licensed and certified plasma center, click here.

Sell your poo, save a life

Payout (per donation): $40

It may sound gross, but donating what you'd normally dump down the toilet can be a beautiful thing for someone else's microbiome.

Researchers at the non-profit stool bank Open Biome in Massachussets collect and freeze fecal samples to help patients dealing with potentially deadly C. Difficile infections. Patients with "C. Diff," as it's often called, suffer from an inflamed colon and their condition is often resistant to antibiotics. But recently researchers have figured out they can jumpstart the sick guts of C. Diff sufferers using poop injections from super-healthy people.

There are a couple of caveats to be aware of here, though: the project is largely for Bostonians, since you'd have to live near one of the three Open Biome donation centers in the Boston area. You'd also have to drop off your (ahem) donations at least three times a week for 60 days. And you need to be really healthy and fit: the Open Biome centers only accept around 4% of applicants, according to the Washington Post.

Women: Donate your eggs

Payout (per donation): usually $8,000 to $14,000

Egg donation allows women whose ovaries do not produce healthy eggs to become pregnant using another woman's donated eggs. In the United States, The American Society of Reproductive Medicine used to suggest it was "not appropriate" for women to be paid more than $10,000 for their eggs, but in 2016, the ASRM scrapped that guideline as part of a federal anti-trust settlement.

At Weill Cornell Hospital in New York City, the compensation per egg donation cycle today is exactly $10,000, and includes a free medical screening. The medical college outlines the standard steps for egg donation, which requires about a four-week time commitment.

During the donation cycle, patients are injected with fertility drugs so that their ovaries make more eggs. (Eligible women are generally between the ages of 21 and 35). The actual egg retrieval procedure takes about 20 minutes, but may require several days of recovery.

Women should be aware of the risks involved in the egg donation process before signing up. Complications can include health problems like long-term abnormal tissue growth outside the uterus (endometriosis), moodiness, infection, kidney damage, and in rare cases, death. Donating eggs might even cause cancer, though scientists say it'll take decades to know for sure if there's a link.

And of course since children born from donated eggs will share common DNA with their donor, women who donate should also be aware that the children they help create may some day want to reach out and make contact.

But donating semen can add up to more than just extra pocket change. Many programs require a six-month or one-year donation commitment. Manhattan Cryobank say it pays donors $1,500 a month for their sperm.

Generally, sperm banks are a bit picky about choosing donors. They’re looking for men who are healthy, relatively tall (usually at least 5’7”), young (under 40), and educated.

Oh and there’s one more thing for sperm donors to bear in mind: even if you choose to donate anonymously, sperm donation is never really 100% incognito. Your DNA always knows who you are, and with the rise of more DNA testing services, your offspring could one day reach out to say hi.

Lie in bed for 70 days straight

Payout: $18,000

NASA will pay you to go straight to bed.

But there's a catch: you have to stay there for up to 70 days, 24 hours a day. These bed-rest studies help NASA researchers see some of the changes that an astronaut's body goes through due to the weightlessness of space flight. If you're interested in applying, you can learn more about bed rest studies here.

If you think getting paid to lay down for a few months sounds like easy money, keep in mind that the selection committee is looking for participants that possess the physical and psychological traits of a real astronaut. You'll have to keep your head tilted down six degrees at all times while you lay there, even when you're showering and eating.

Roni Cromwell, a senior scientist for the study told Forbes: "We want to make sure we select people who are mentally ready to spend 70 days in bed. Not everyone is comfortable with that. Not every type of person can tolerate an extended time in bed."

Become a surrogate mother by carrying someone's baby in your womb

Payout: $24,000-$45,000

Women who carry a baby for another couple can make quite a hunk of extra cash for their nine-month child incubation, known as a "gestational surrogacy."

But enlisting and paying for a surrogate mother is not legal everywhere. State laws around surrogacy in the US are complicated and contradictory. In New York and in Michigan, there's a ban on surrogacy contracts, and you can serve jail time or pay hefty fines for going through with one. Some lawmakers are pushing to change those rules, though.

Sign up for a paid clinical trials

Payout: Varies by program

The National Institute for Health runs a searchable database, ClincalTrials.gov, for human clinical studies around the world. Participants may be guinea pigs for new medical products, like drugs to treat high blood pressure, or take part in observational research, like a study that records the effects of different lifestyles on heart health.

Subjects are generally paid to be a part of clinical trials, and in general, the bigger the risk, the bigger the reward.

Enroll in a psychological study

Payout: Varies by program

Paid psychological studies, such as those that examine human behavior and brain function, may not generate as high of a return as clinical trials, but they are generally lower risk and require a shorter time commitment.